1. Field of the Invention
This invention relates to a new formulation for ingredients of detergents and/or cleaning products, particularly laundry detergents, to correspondingly formulated detergents and/or cleaning products and to the new process for their production. More particularly, the invention relates to the production of a comparatively coarse-particle and permanently free-flowing material which, on the one hand, is compacted to high apparent densities but which, on the other hand, is capable by virtue of its special structure of rapidly interacting with liquid phases, particularly aqueous liquid phases, so that the particle structure is destroyed.
2. Discussion of Related Art
In recent years, there have been many proposals relating to the production of solid, powder-form or agglomerated granular detergents and/or cleaning products having high apparent densities. From the more recent past, reference is made to EP 340 013 and to the documents cited therein EP 219 328, EP 270 240 and GB 1,517,713 (all Unilever), EP 229 671 and JP 61 069 897 (Kao) and also to EP 220 024 (Procter & Gamble). The first of these documents describes granular detergent mixtures having an apparent density of at least 650 g/l which are obtained by mixing selected non-soap-like surfactants (at least partly corresponding anionic surfactants) in certain ratios with predeterminated quantities of crystalline or amorphous sodium aluminium silicate. The granules are said to be produced in a high-speed mixer/granulator which carries out the mixing and size reduction steps of the process. The process is carried out in the presence of a liquid binder, the preferred binder being water which, if necessary, may be added before or during the granulation step. According to the Examples, the particle size of the agglomerates obtained in this way is well below 1 mm and, in general, is in the range from about 400 to at most 600 .mu.m.
A more recent proposal from the same applicants can be found in EP 367 339. This document also describes the production of comparatively fine detergent granules having apparent densities of at least 650 g/l. The production process is now said to be carried out in two stages: the fine-particle mixture of active substances is treated in a high-speed mixer and, at the same time, compacted in a first process step (5 to 30 seconds) and, in a following second process step, the compacted material is granulated at lower throughputs over a period of about 1 to 10 minutes, again with simultaneous compaction of the material. The material thus obtained is said to be dried and/or converted by cooling into the free-flowing state. The Examples of this document are concerned with comparing the respective apparent densities and the associated percentage particle porosities and particle sizes. It is shown that the described two-stage process provides for a distinct increase in apparent density--for example to values of up to about 950 g/l--accompanied by a substantial reduction in percentage particle porosity. Whereas the powders obtained by spray drying have apparent densities of around 400 g/l for a particle porosity of 45 to 50%, the apparent densities of the material compacted in two stages are in the range from about 700 to 900 g/l while particle porosity can be reduced to values below 20% and, in particular, below 10%. The particle size of the compacted material can reach a value of approximately 1 mm, but once again is generally well below that value.
In German patent application DE 39 26 253, the applicants responsible for the development disclosed in the following describe a new process for the production of solid free-flowing granules of detergents and/or cleaning products, more particularly corresponding laundry detergents. These granules are distinguished by apparent densities of at least about 700 g/l and preferably in the range from about 850 to 1,000 g/l. The granules are produced by extrusion using only very small quantities of liquid phase, particularly water, and in a preferred embodiment are additionally dried by removal of water in a following step. This process gives dry granules combining high density and high strength with high stability in storage under ambient conditions. The process described in this earlier application is characterized by intensive compounding of the mixture in screw extruders using high shear forces and processing pressures and, at the same time, by plasticization of the mixture. The compound homogenized in this form is extruded in the form of strands through perforated plates, the compacted strands issuing from the extruder are then cut to the predetermined size of the granules and, if desired, rounded before the individual granules are, if necessary, treated with other active substances and/or dried to form the granular free-flowing material.
The problem addressed by the present invention was to enable selected modifications to be made to the particular composition of the compacted, comparatively coarse granules without changing their granular appearance. More particularly, the problem addressed by the present invention was to enable the internal structure and, in particular, the microporosity of the granules to be controlled. The teaching of the invention was intended to enable the inner surface of the granules to be influenced, preferably in such a way that a large inner surface could be established in the granules despite high compaction of the mixture. In this connection, the particular object to be achieved by the invention was to ensure that the granular concentrates would dissolve rapidly and thoroughly in the wash liquor despite their high apparent densities. It is clear that the redissolvability of the granules can be influenced by increasing the inner surface of the granules, particularly through the inclusion and protection of very fine, microdisperse entrapped air.
Another important determining element of the process for producing concentrates with the new structure pursues the same objective, namely: the compaction and pressing of the material should be possible with hardly any need for the particular mixture to be exposed to shear forces. In particular, the smearing of the individual solid particles against one another which occurs, for example, when the corresponding solid mixtures are processed in screw extruders on account of their highly pronounced shear effect should be prevented as far as possible. This aspect is of particular significance in the case of auxiliaries and ingredients of detergents and/or cleaning products insofar as very greasy components, such as surfactants, polymeric builders and other mixture components deformable or even spreadable under pressure, are generally used in their case.
Another problem addressed by the invention was to enable permanently free-flowing concentrates combining high breaking strength with a minimal tendency of the individual particles to stick to one another during storage to be produced. In one important embodiment, the invention sought to enable compacts of the described type to be obtained as direct products of the process without any need for an intermediate drying step.
To solve these various problems, the invention provides a series of constructive elements concerning the composition of the granules or compacts on the one hand and the process parameters involved in the production of the compacted concentrates from the at least predominantly powder-form starting materials.